The folly of drafting team defenses

The trouble with picking a team defense based on last year.

There has been a movement in fantasy football to drop team defenses from starting requirements, but the mass majority of leagues still require them. Defenses yield the sense that you own “an entire team” and that you are not just picking a collection of disparate and unrelated players for a statistical game of probability (umm… anyway).

The problem with team defenses is that they are far more challenging to predict. On offense, the best players are given the most chances to succeed. Defenses can only react to whatever the opposing offense does and they will intentionally try to steer clear of the strength of a defense.  The best running back gets the most carries. The best cornerback may never see a pass his way.

There is a myriad of different scoring systems used with team defenses, but most just consider sacks, turnover recoveries, safeties, and touchdowns. That’s what the below rankings are based on. Other measurements are sometimes used – points allowed, yardage allowed, return yardage, etc.. But mostly – just sacks, turnovers, safeties and touchdowns.

Nothing has a bigger impact on a fantasy draft than what just happened the previous year. Here are the current Average Draft Positions for team defenses and where each ranked at the end of 2019. Green cells show a finish in the Top 6 as an advantage, No. 7 to No. 12 are white – worth starting but not as advantageous, and then the red is No. 13 and beyond – no advantage.

The Bears were #3 in 2018, so people expect them to return. The Bills also seem to have a better defense than their fantasy points usually support. But overall, the top six defenses of 2019 are very well represented in 2020 drafts and they were the only defenses that gave a fantasy team any advantage last year.

So, taking that early defense looks good and feels good, right? I know – I’ve done it plenty of times. And it rarely pays off, amigo. Here are the actual results from the last five years, sorted on the 2018 season so you can see how well those top defenses repeated last year.

Ouch.

Take a look through the last five years. That’s all true in any year of the NFL – defenses are just very hard to call correctly in fantasy football. They are a very complex group of players reacting to a different offense every week.

Take a defense. Take two if you want. But spending an extra early pick rarely pays off and watching the waiver wire closely for the first month of the season is a better way of determining which team defenses are stepping up this year, at least more accurately than expecting 2019 to repeat.